I put Alex down a year ago. She had cancer. She was a great hunting companion. She was more than that to me and as a result I was always trying to get her to do new stuff, and she was always willing to learn. She was 8 1/2 years old. You can teach your new dog anything as long as you are bonded. What you need to do is work patiently and steadily with your new pup. Do short training sessions but do them often, and play with him in between those sessions. Get yourself a copy of THE TEN MINUTE RETRIEVER and use it. I have no doubt that your new pup can be retrained and molded into the dog you want. Good luck and let us know how you are making out from time to time.